This was one of the last "plain" semilente[4] insulins marketed. Novo Nordisk distributed it in Germany, but not in places like the US, Canada and the UK. Semilente insulin [5] has an activity pattern similar to that of R/Neutral.

The MC (stands for Monocomponent) designation seen in the insulin's name means it is of animal origin and highly purified. In some markets, Novo Nordisk "coded" their insulin in this manner: MC was insulin of animal origin, while HM was of r-DNA/GE/GM origin. In the past, the MC designation could mean it was made of beef, of pork, or a blend of both, as it was a way of distinguishing highly purified beef and pork insulins. Seeing it prior to its discontinuance means the insulin was of pure porcine origin, as Novo discontinued its bovine insulins some time ago.

Before the invention of VetPen, Lente-type insulins could not be dispensed in pen or cartridge form because the glass ball formerly used to mix the insulin in these devices shattered the Lente crystals.[13]